Lung cancer is the second most common cancer both in women and men, reports the American Cancer Society. Lung cancer accounts for 15 percent of all new cancers. The three most common types of lung cancer are squamous cell carcinoma of the lung, adenocarcinoma of the lung and large-cell carcinoma of the lung. All three are non-small-cell lung cancers.
Squamous Cell Carcinoma
Squamous cells are round cells that replace damaged cells on numerous organs, including the airways in the lung. This type of cancer accounts for 25 to 30 percent of all lung cancers. Squamous cell carcinoma usually occurs in the center of the lung, states the University of Maryland Medical Center. The cancer originates in a major lobe of the lung or in a main airway. The cancer can grow very large and create holes in the lung. Squamous cell carcinoma of the lung is closely associated with a history of smoking.
Adenocarcinoma
Adenocarcinoma is a cancer of the mucous glands in the lungs. This type of cancer accounts for 40 percent of the all cases of lung cancer and is the most common type, reports the American Cancer Society. It originates in the outer areas of the lung. Adenocarcinoma can be very aggressive and most commonly spreads to the brain. Most cases of adenocarcinoma in the lung are diagnosed when the cancer has already progressed to its later stages. Recently adenocarcinoma of the lung has been strongly associated with smoking.
Large-Cell Carcinoma
Large-cell carcinomas can occur in any part of the lung, according to Medline Plus, a National Institutes of Health website. This type of cancer composes 10 to 15 percent of all lung cancers. Large-cell carcinomas are also called undifferentiated lung cancers. The cells of this type of cancer appear to be large, immature cells under a microscope. Large-cell lung cancer is often more aggressive than other types of lung cancer. It can spread to numerous organs before symptoms are noticed.
